The sixth Duke of Westminster is the U.K.'s wealthiest landowner. His Grosvenor property group has valuable holdings in the posh Mayfair and Belgravia neighborhoods of London where rents have fallen almost a third since last spring. One of group's funds entered into negotiations with banks to refinance its debt. Owns additional land in London via private family trusts; also holds farmland in Northern England and Scotland. Officer in Britain's reserve forces and Chancellor of University of Chester.